Abrasive material transport hose with wear detecting sensors

ABSTRACT

The useful life of an abrasive material transport hose ( 10 ) can be maximized if the hose is repositioned at the first signs of internal wear. This is accomplished by disposing at least two wear sensing elements ( 17, 21 ), each at a specified distance from the inwardmost surface of the inner tube ( 12 ), and each monitoring a condition indicative of wear of the hose ( 10 ) at its specified distance from the inwardmost surface of the inner tube. When the innermost wear sensing element ( 17 ) implies wear, the hose can be repositioned to extend the useful life until the outermost wear sensing element ( 21 ) indicates wear requiring replacement of the hose.

FIELD OF THE INVENTION

The invention relates to a hose for transporting abrasive material andin particular to a hose for transporting abrasive material havingsensors for detecting wear of the hose.

BACKGROUND OF THE INVENTION

A hose for transporting abrasive material, either fluidized or dry bulk,is usually constructed with an inner lining or tube made of abrasionresistant material, a carcass composed of layers of reinforcement pliesto resist pressure within the tube and a rubber cover, typically of anelastomeric materials, to protect the carcass. The hose may include, areinforcing steel wire helix embedded between the layers and a built-incoupling at each end.

Since the hose is used for transporting abrasive material, the innerlining and reinforcing layers of the hose can be worn through by theflow of the material during usage. Since the wear is within an internalsection of the hose, it is not possible to visually inspect the degreeof wear. The hose, if operated until total failure, can createunforeseeable and unwanted problems including leakage, rupture orexplosion.

U.S. Pat. No. 4,446,892 ('892) by Maxwell discloses a fluid transporthose having two or more plies comprising a sensing element locatedbetween the plies, the sensing element being adapted to respond to thefailure of an inner ply of the hose by presenting an open circuit. Thepurpose of the sensing element in the hose is to detect imminentbreakdown of a hose section and to permit the user to replace the hoseprior to external leakage. The '892 patent also discloses a secondarysensing element disposed between the outermost plies of the hose todetect the occurrence of physical damage to the outer plies of the hose.

U.S. Pat. No. 5,634,497 ('497) by Neto discloses a hose for suction anddischarge of abrasive material with a sensor circuit which indicates thetotal or partial wear of the inner lining of the hose, thus permittinghose replacement prior to its rupture or blow up. The '497 patentdiscloses a sensing element comprised of a bi-polar (two-pole) socketfixed to one of the external layers of the hose and connected,preferably, to the terminal ends of wires which extend spirally alongthe entire length of the hose. In order to determine the wear of thehose, it is necessary to verify, by means of the bi-polar socket, thecontinuity of the sensing element. In the case where the sensing elementis interrupted, this means that the wire wound within the hose has beenbroken, implying that the hose shows signs of internal wear and shouldbe replaced.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved hoseusing a sensing system to detect the internal wear of a hose, as definedin one or more of the appended claims and, as such, having thecapability of being constructed to accomplish one or more of thesubsidiary objects.

It is another object of the present invention to provide a hose capableof transporting abrasive material, either dry bulk or fluid.

It is a further object of the present invention to detect wear of thehose without interrupting the transport of the abrasive material.

It is yet another object of the present invention to detect wear of thehose to avoid an operating accident such as leakage, rupture, andexplosion.

It is still another object of the present invention to provide multiplelevels of hose wear detection in order to permit hose reposition priorto replacement in order to maximize the hose's useful life.

It is an object of the present invention to provide a hose with awear-sensing element, which can be disposed within the tube or betweenthe reinforcement plies of the hose using either wire or chemicallysensitive tape.

In accordance with the invention, a hose for transporting abrasivematerial comprises first and second wear-sensing elements, one disposedat a first distance from the innermost surface of the inner lining(tube) and a second disposed at a second distance from the innermostsurface of the inner lining (tube), the second distance being greaterthan the first distance. By monitoring the first and second wear-sensingelements with wear sensing devices, it is possible to detect wear of theinner lining and further wear as it propagates to one of the many layersdisposed over (radially outward) the inner lining.

The first wear-sensing element is disposed adjacent to or within theinner lining (tube) or one of the reinforcement plies, runningsubstantially the entire length of the hose. The first wear-sensingelement, made up of a first set of two sensor wires, extends spirallyover the length of the hose. One end of the first set of two sensorwires making up the first wear-sensing element are joined together. Theother end of the first set of two wires making up the first wear-sensingelement are connected to a first two-pole socket.

The second wear-sensing element comprises a second set of two sensorwires, each of the two sensor wires having one end extending to or evenbeyond one end of the hose and an opposite end extending to or evenbeyond the other end of the hose and joined (spliced) together. At theone end of the hose, the second set of sensor wires are connect to asecond two-pole socket.

The means or structural components to detect wear is provided byconnecting to the first and second two-pole sockets, through which thefirst and second wear-sensing elements can be monitored. Sensing wear atthe first, innermost wear-sensing element permits the user to repositionthe hose so as to continue operation until wear is sensed at theoutermost second wear-sensing element, at which point the hose needs tobe replaced prior to its failure during use. Repositioning the hoseafter sensing wear in the innermost layers of the hose extends theuseful life of the hose.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure, operation, and advantages of the present preferredembodiment of the invention will become further apparent uponconsideration of the following description taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a perspective view, partial cutaway, of a section of anembodiment of a hose of this invention incorporating sensor wire appliedover the length of the hose;

FIG. 2 is a perspective view of the hose of FIG. 1, showing a laterstage of construction, incorporating two-pole sockets connected tosensor wire and assembled on the hose;

FIG. 3 is a perspective view of the hose of FIG. 2 showing a completedhose of this invention, incorporating two wear sensor circuits and awear-sensing device attached to each circuit;

FIG. 4 is a detailed view of a wear-sensing device of FIG. 3, includinglocal annunciation and optional remote station connection;

FIG. 5 is a simplified schematic block diagram of a hose wear-sensingdevice of FIG. 4; and

FIG. 6 is a perspective partial cut-away view of a section of anotherembodiment of a hose of this invention.

DETAILED DESCRIPTION OF THE INVENTION

A hose for transporting abrasive material wears due to the effects ofcontact with the material being transported. Wear initiates on the innerlining and then propagates to subsequent reinforcement layers untiltotal failure of the hose occurs, resulting in leakage, rupture, orexplosion.

From the prior art, it is known that wire may be disposed in a hose inorder to detect the wear of inner layers to permit replacement prior tototal failure of the hose. Wire used for this purpose is called “sensorwire”. A “wear sensing element” comprises a layer of sensor wire in ahose. A layer of hose surrounded by a wear-sensing element is called a“sensed layer”. A device used to monitor a wear sensing element iscalled a “wear sensing device”. A “wear sensing system” comprises a wearsensing device attached to a wear sensing element.

A sensed layer, either an inner lining (also called a tube herein) or areinforcement ply covering the tube, wears due to the effects of theabrasive material being transported. Once the sensed layer has wornthrough, the abrasive material can make contact with and cause wear ofthe sensor wire in the wear sensing element. A wear sensing systemdetermines whether the wear sensing element is worn by testing forcontinuity. The presence of continuity of the wear sensing elementimplies that the sensed layer is not worn. Conversely, the absence ofcontinuity of the wear sensing element implies wear of the sensed layer.

A hose of the present invention includes at least two distinct wearsensing elements. The use of multiple wear sensing elements permits thedetection of wear at different depths of the hose. As is commonlyunderstood in the industry, the wear of a hose in abrasive materialapplications typically occurs at specific points within the hose,typically where the hose has a bend in it. The wear sensing element forthe innermost sensed layer provides the first indication of hose wear.Wear detected at the innermost sensed layer permits the user to knowwhen a hose should be repositioned (typically rotated) to transfer thematerial abrading to other locations of the hose inner layers, therebyextending the useful life of the hose. This process can be repeateduntil wear is detected in the outermost wear sensing element, implyingwear in the outermost sensed layer, indicating the need for hosereplacement.

The aforementioned U.S. Pat. No. 5,634,497 to Neto discloses a hose withtwo layers of sensor wire arranged so as to form only one wear sensingelement. In contrast thereto, the hose of the present invention has atleast two wear sensing elements and corresponding at least two wearsensing systems arranged such that, in the case of two wear sensingelements, the inner wear sensing element detects the initiation of wearin the inner lining and the outer wear sensing element detectspropagation of wear to a subsequent, outwardly disposed reinforcementlayer.

U.S. Pat. No. 4,446,892 to Maxwell discloses a hose with two wearsensing elements, the sensing elements arranged such that the innersensing element detects wear in the inner lining, and the outer sensingelement detects damage to the hose exterior. In contrast thereto, the atleast two sensing elements of the present invention are arranged suchthat the progress of a wear problem can be “tracked” as it propagatesfrom the inner lining to subsequent reinforcement layers.

FIG. 1 shows a preferred embodiment of the hose 10 for transportingabrasive material of the present invention in a partially completedstage of construction. The hose 10 has two ends 10 a and 10 b, andcomprises an inner, preferably wear-resistant elastomeric lining (tubeor tubes) 12 having an innermost surface 11. A first set of sensor wires14 and 16 are spirally wound on the inner lining 12 and extend to oreven beyond both ends of the hose 10. The first ends 14 a and 16 a ofthe sensor wires 14 and 16, respectively, extend to or even beyond theend 10 a of the hose 10 and are connected to a two-pole socket 42. Theopposite second ends 14 b and 16 b of the sensor wires 14 and 16,respectively, extend to or even beyond the opposite end 10 b of the hose10 and are connected (spliced) to one another.

In this manner, the two sensor wires 14 and 16 effectively form a singlewear sensing element 17 extending along the entire length of the hose 10over a “sensed layer” 13. The single wear sensing element 17 has twoends 14 a and 16 a which typically extend to one end 10 a of the hose10. As described hereinbelow, the ‘free ends’ 14 a and 16 a of wires 14and 16, respectively, are connected to a conventional two-pole socket42, and a wear sensing device 60 is attached to the wear sensing element17 via the socket, to form a “wear sensing system” 19. According to theinvention, additional wear sensing elements 21 may be formed in the hose10 to monitor progress of abrasion as it propagates from the sensedlayer 13 of the hose towards an outer sensed layer 23 of the hose.

The second sensed layer 23 of tube or reinforcement ply is applied overthe wear sensor wires 14 and 16. In a manner similar to that describedhereinabove with respect to the wear sensing element 17, a pair ofsensor wires 20 and 22 are spirally wound around the layer 18 ofreinforcement ply and typically extend to or even beyond both ends 10 aand 10 b of the hose 10. The free ends 20 a and 22 a of the sensor wires20 and 22 can extend to or beyond the end 10 a of the hose 10 and areconnected to a conventional two-pole socket 44. The ends 20 b and 22 bof the sensor wires 20 and 22 extend to or beyond the opposite end 10 bof the hose 10 and are connected (spliced) to one another to complete asecond wear sensing element 21. The wear sensing element 21 is used todetect wear in the “sensed layer” 23.

In this manner, two wear sensing elements 17,21 are provided in the hose10. The first wear sensing element 17 comprises the sensor wires 14 and16 and is disposed at a first distance from the most inner surface 11 ofthe inner lining 12. The second wear sensing element 21 comprises thesensor wires 20 and 22 disposed at a second distance which is greaterthan the first distance from the most inner surface 11 of the innerlining 12.

Additional layers of reinforcement ply, as represented by ply layers 24,26, 28, 30 (24-30), are disposed over the sensed layers 12 and 23. Inaddition, reinforcing steel wire helix wires (not shown) can be embeddedbetween the ply layers as is conventionally known in the hoseconstruction art. In the manner described hereinabove, additional wearsensing elements can be incorporated into the hose construction, overany one of these additional ply layers, at increasing distances from theinner surface 11 of inner lining 12, to provide additional levels ofwear detection, as may be desired.

FIG. 2 shows a further stage of construction of the hose 10 of thepresent invention. On the outmost shown layer 40 of reinforcement ply,first and second two-pole sockets 42,44 are affixed by any conventionalmeans, and are connected to free ends 14 a, 16 a and 20 a, 22 a,respectively, of the sensor wires 14,16 and 20,22 of sensing elements17,21, respectively. At the opposite end of the hose 10, free ends 14 b,16 b, 20 b, 22 b of the sensor wires 14, 16 and 20, 22 are splicedtogether as shown in FIG. 1. While the wires 14,16 and 20,22 are shownspliced together, it is within the terms of the present invention tojoin them in any conventional manner including forming them of a singlelength of sensor wire. As shown in FIG. 2, sensor wires 14,16 and thefirst two-pole socket 42 represent the first wear sensing element 17 andsensor wires 20,22 and second two-pole socket 44 represent the secondwear sensing element 21.

FIG. 3 shows a completed construction of a typical hose 10 of thepresent invention. The hose 10 receives an outermost cover layer 50 toprotect the plies 24-30 forming the hose carcass, thus enclosing thetwo-pole sockets 42,44 (shown in FIG. 2) and exposing terminal ends52,54, respectively. While the sockets 42,44 are shown as being mountedwithin the hose 10, it is also within the terms of the invention tomount the sockets on the exterior of the hose, i.e. upon the cover layer50, so that they can be easily replaced with other sockets depending onthe particular installation. A user inserts plugs 56,58 of wear sensingdevices 60,62 (described hereinafter with regard to FIG. 4) intoterminal ends 52,54, respectively, of two-pole sockets 42,44 to detectthe degree of internal wear of hose 10.

Hose 10 is generally constructed in accordance with techniques alreadyknown for manufacturing of hoses used for transporting abrasivematerials. For example, hose 10 may be constructed with various innerdiameters of interior surface 11 as well as different final lengths.However, the hose usually has an inner diameter in the range of from 2.5to 120 cm (1 to 48 inches).

Another embodiment of the present invention may be considered (notshown) where sensor wire 14,16 is replaced with a chemical sensitivetape for application where material being transported is of a naturesuch that its presence may be sensed by means other than continuity.That is, the chemical sensitive tape can function as the sensor wires byindicating that the sensed layer about which the chemical sensitive tapeis wrapped is worn by the absence of electrical continuity through thetape caused by chemical erosion or wear of the tape.

FIG. 4 shows a typical wear sensing device 60 (substantially identicalwith wear sensing device 62) comprising an ON/OFF switch 72, a powersource (not shown), an LED 74, a buzzer 76, a Push-to-Test button 78, abuzzer select/deselect switch 80, an optional remote output 82, and anindustrial strength RCA phono jack 56 (comparable to plug 58 of wearsensing devices 62) for connecting to the first and second two-polesockets 42,44 of sensing elements 17,21. Internally (not shown), thewear sensing device 60 contains a wear monitor circuit (describedhereinbelow with respect to FIG. 5) to monitor a wear sensing element17,21 and control an alarm circuit.

Functionally, a wear sensing device 60,62 monitors a sensing element17,21 by constantly checking continuity (resistance) of the circuit. Afunctioning circuit will measure a resistance, such as for example, lessthan 10,000 ohms that indicates that continuity of the sensing elementis intact, implying that the sensed layer is functioning as required.Measuring a higher resistance, such as for example, greater than 100,000ohms, indicates that continuity of the sensing element 17,21 has beenbroken, implying that the sensed layer has malfunctioned. In the latterinstance, the functioning circuit activates an alarm 75. Alarm 75consists of a flashing LED 74, an audible buzzer 76, and an optionalsignal from output 82 for a remote Programmable Logic Controller (PLC).Any or all of these alarms may be deployed, depending on the usage.

FIG. 5 shows a simplified block diagram of a hose wear monitor circuit80 of a wear sensing device 60,62. The circuit 80 includes an InputInterference and Overvoltage Protection circuit 90, which connects byoutput 91 to a wear sensing system 19,23 and protects the correspondingwear sensing device 60,62 from external noise and voltage spikes. Thewear monitor circuit 80 also includes a Resistance Monitoring circuit92, which measures the resistance of a wear sensing elements 17,21 todetermine if continuity is present. A Multivibrator and Oscillatorcircuit 94 flashes an LED 96 if an alarm condition is present. Using aBuzzer Select/Deselect switch 98 the operator enables an audible alarm100. A separate transistor output 102 can also be included as part ofthe wear sensing device 60. A device such as a Programmable LogicController (PLC) (not shown) monitors the transistor output 102 toannunciate alarms in a centralized control room or other remotelocation. A Push-to-Test switch 104 verifies proper operation of thewear sensing device 60. An ON/OFF switch 106 controls power flow to thewear sensing device 60 from conventional means such as a 6V batterycircuit 108.

ALTERNATE EMBODIMENT

FIG. 6 shows a hose 110 constructed in accordance with a secondembodiment of the present invention. Over a mandrel (not shown), aninner lining or tube 112 is applied, upon which a sensor wire 114 isspirally wound thereabout. Subsequently, an additional layer ofinsulating liner or tube 116 is applied, upon which a sensor wire 118 isspirally wound. The free ends 114 a, 118 a of sensor wires 114,118,respectively, are extended to or even beyond one end of the hose 110 andconnect to a first two-pole socket (not shown but comparable to two-polesocket 42) as described hereinbefore. The other free ends 114 b, 118 bof sensor wires 114,118, respectively, are joined or spliced together tocomplete a first wear sensing element 119 (sensor wires 114,118 andtwo-pole socket 42) to detect wear in sensed layer 113. Subsequently, alayer 120 of tube or reinforcement ply is disposed over insulating tubeor fabric layer 116. Layer 120 in turn has a single turn of sensor wire122 spirally wound thereabout. A layer 124 of insulating tube or fabricis next applied, upon which a single turn of sensor wire 126 is spirallywound thereabout. Next, a reinforcement ply 128 is disposed over thelayer 124 and sensor wire 126. The free ends 122 a, 126 a of sensorwires 122,126, respectively, extend to or even beyond one end of thehose 110 to connect to a second two-pole socket (not shown) in themanner described hereinbefore regarding the embodiment shown in FIGS. 1and 2. The other free ends 122 b, 126 b of sensor wires 122,126 arejoined or spliced together to complete a first sensing element 119. Itis within the terms of the invention to provide wires 122,126 from asingle strand of sensor wire that is simply applied on the inner layer120 and then applied on the outer layer 124. The first sensing element119 detects wear in sensed layer 113. Subsequent layers of sensor wires,carcass fabrics, tubes and reinforcement plies can be applied using thismethod depending on the number of wear sensing elements andreinforcement plies required for the usage.

Completion of the construction of the embodiment presented in FIG. 6 issimilar with the construction method described regarding the firstembodiment illustrated in FIGS. 2 and 3. The second embodiment can beconnected to wear sensing devices such as devices 60,62 as describedhereinbefore.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

What is claimed is:
 1. A hose for transporting abrasive materialincluding an inner lining, a plurality of layers of reinforcement plydisposed over the inner lining, a first wear sensing element disposed ina first sensed layer at a first distance from the innermost surface ofthe inner lining, the hose characterized by: a second wear sensingelement in a second sensed layer disposed at a second distance from theinnermost surface of inner lining, the second distance being greaterthan the first distance; a second wear sensing device, connected to thesecond wear sensing element for providing an indication of propagationof a hose wear condition from the first sensed layer to the secondsensed layer; the first wear sensing element comprises a first pair ofsensor wires each having a first end extending to a first end of thehose and a second end extending to a second end of the hose; and thesecond wear sensing element comprises a second pair of sensor wires eachhave a first end extending to the first end of the hose and a second endextending to the second end of the hose; the second end of the firstpair of sensor wires are connected to one another; and the second end ofthe second pair of sensor wires are connected to one another.
 2. Thehose according to claim 1, characterized in that: the first pair ofsensor wires are insulated from each other by a layer; and the secondpair of sensor wires are insulated from each other by a reinforcementlayer.
 3. The hose according to claim 1, characterized in that: thefirst ends of the first pair of sensor wires are connected to a firstsocket; and the first ends of the second pair of sensor wires areconnected to a second socket.
 4. The hose according to claim 3,characterized in that: the first and second wear-sensing device forproviding an indication of wear from the innermost surface of innerlining to the first and second sensed layers are connected via the firstand second sockets, respectively, to the first and second pairs ofsensor wires, respectively.
 5. A hose for transporting abrasivematerial, characterized by: an inner lining of elastomeric tube(s), twoor more reinforcement layers applied over the inner lining, an outercover applied over the outermost one of the reinforcement layers,wherein the hose has a length and two ends, characterized by: a firstwear sensing element disposed at a distance from an interior surface ofthe hose, for indicating a wear condition resulting from transportingthe abrasive material; a second wear sensing element, disposed in asecond sensing layer between the reinforcement layers, at a greaterdistance from the interior surface of the hose, comprising a pair ofsensor wires running substantially the entire length of the hose, andhaving one end of the sensor wires connected with one another and theother end connected to a second wear sensing device, said second wearsensing element also for indicating a wear condition resulting fromtransporting the abrasive material; and the pair of sensor wires of thesecond wear sensing element extend spirally over the length of the hoseand are connected at end to a socket.
 6. The hose according to claim 5,characterized in that: the first wear sensing element is disposedbetween the innermost surface of inner lining and a first sensing layer.7. The hose according to claim 6, characterized in that: the first wearsensing element has two sensor wires, each having an end at the one endof the hose and connected to a first wear sensing device, and anotherend extending to the other end of the hose, and the ends are connectedto one another.
 8. The hose according to claim 7, characterized in that:the sensor wires of the first wear sensing element extends spirally overthe length of the hose.
 9. The hose according to claim 6, characterizedin that: the wear sensing element is disposed in a second sensing laserbetween the reinforcement layers which is farther from the innermostsurface of inner lining than the first sensing layer.
 10. The hoseaccording to claim 9, characterized in that the first and second wearsensing devices connected to the wear-sensing elements, respectively,provide an indication to the user when the hose has worn through to theinnermost wear-sensing element, thereby permitting the user toreposition the hose so as to continue operation until a failure of thesecond wear-sensing element to maximize the useful life of the hose.